feat: initial Swift version

QLPreview/PreviewViewController.swift

@@ -0,0 +1,25 @@
+import Cocoa
+import Quartz // QLPreviewingController
+import WebKit // WebView
+import os // OSLog
+
+// show Console logs with subsystem:de.relikd.QLApps
+private let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "main")
+
+class PreviewViewController: NSViewController, QLPreviewingController {
+	
+	override var nibName: NSNib.Name? {
+		return NSNib.Name("PreviewViewController")
+	}
+	
+	func preparePreviewOfFile(at url: URL) async throws {
+		let html = generateHtml(at: url)
+		// sure, we could use `WKWebView`, but that requires the `com.apple.security.network.client` entitlement
+		//let web = WKWebView(frame: self.view.bounds)
+		let web = WebView(frame: self.view.bounds)
+		web.autoresizingMask = [.width, .height]
+		self.view.addSubview(web)
+		web.mainFrame.loadHTMLString(html, baseURL: nil)  // WebView
+		//web.loadHTMLString(html, baseURL: nil)  // WKWebView
+	}
+}